1. Field of the Invention
This invention generally relates to the field of oil and/or gas exploration and production and more specifically relates to an apparatus and method for maintaining a wellbore.
2. Description of the Related Art
Wells drilled for producing oil and/or gas extend from the surface through a subterranean formation where they intersect a hydrocarbon bearing strata. The wells may include one or more lateral wells that intersect a primary wellbore and extend into the formation away from the primary wellbore. The lateral wellbores typically are formed to produce from a particular hydrocarbon laden zone identified away from the primary wellbore. Additionally, utilizing lateral wellbores enables production from a much larger area while limiting drilling costs to a single primary wellbore.
From time to time, however, lateral wellbores may require inspection and/or repair. Locating and entering these lateral wellbores can sometimes be difficult due at least in part to the uncertainties inherent in defining the direction of the lateral within the main wellbore. This is especially so when disposing a downhole tool on coiled tubing or wireline. Known devices available for locating a lateral wellbore include mechanical locators provided within the well that can be identified by various means. With reference now to FIG. 1, an example is shown in a side partial sectional view of a wellbore 2 formed through a subterranean formation 4. In this example, the wellbore 2 comprises a primary wellbore 3 with lateral wellbores 5, 6, 7 intersecting the primary wellbore 3 at various locations along its length.
A wellbore operations system 10 is shown inserted into the wellbore 2. The system includes a downhole tool 18 deployed in the primary wellbore 3 on a length of tubing 14. The tubing 14 is provided from a reel 12 shown threaded through a wellbore tree 16 mounted on the upper end of the wellbore 2. Further illustrated in FIG. 1 is a whipstock 20, which is a simple example of an entry device for directing the tool 18 into the lateral wellbore 7. Also shown in the example of FIG. 1 is water and/or gas 22 emanating from within the lateral wellbore 7 and into the primary wellbore 3. Addressing unwanted water and/or gas production from a lateral well is one example of downhole operations that can be performed in a lateral well.